23 lines
1.1 KiB
Markdown
23 lines
1.1 KiB
Markdown
---
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layout: post
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title: Limited Support for XDF Diskettes
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date: 2014-10-28 11:00:00
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category: Releases
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permalink: /blog/2014/10/28/
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---
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[PCjs v1.15.7](https://github.com/jeffpar/pcjs/releases/tag/v1.15.7) adds support for the
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[XDF Diskette Format](http://www.os2museum.com/wp/the-xdf-diskette-format/), which was used in
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[PC-DOS 7.00](/disks/pcx86/dos/ibm/7.00/).
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However, this support is referred to as "fake" XDF support, because it requires using JSON disk images created
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by DiskDump *without* the experimental "--xdf" option, which is an option that attempts to encode XDF sectors as they
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existed on the original diskettes (ie, with varying lengths and non-standard sector IDs).
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"Fake" XDF support works by using conventional 80-track disk images with 23 sectors/track. No standard PC floppy disk
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format ever used 23 sectors/track, but in this case, by distributing the XDF track data across 23 conventional 512-byte
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sectors, the PC-DOS 7.00 Setup code that reads XDF disks succeeds. This was probably one of several fall-back options
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built into the PC-DOS XDF code.
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*[@jeffpar](http://twitter.com/jeffpar)*
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*October 28, 2014*
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